Answer: Option A.
the author often compares the sound of the cello to a human voice
Step-by-step explanation:
Medium of a story refers to channel system in which information is conveyed and communication occur.
This process allows the main story or plot in a story to be effectively delivered in a way it will be well understood or processed.
For example drama, novel can be a medium where information is conveyed or process.
The author often compares the sound of the cello to a human voice is the correct answer.